Family : Rubiaceae
Text © Pietro Puccio
English translation by Mario Beltramini
The species is native to the forests of western Madagascar.
The name of the genus comes from the Greek adjective “καρφαλέος” (carphaléos) = arid, dry; the specific name comes from the local one.
Common names: flaming beauty, giant pentas (English).
The Carphalea kirondron Baill. (1878) is a shrub or small evergreen tree, up to 3-5 m tall or more if left free to grow up, very ramified.
The leaves, on an up to 2 cm long petiole, are simple, usually decussate (opposite leaves with every pair rotated at right angle in respect to the previous one), rarely in verticils of three, ovate-lanceolate with pointed apex and entire margin, 4-10 cm long and 2-5 cm broad, of glossy dark green colour, coriaceous.
Inflorescences in dense terminal cymes, of 10-25 cm of diameter, bearing numerous flowers with calyx having 4 ovate lobes of bright red colour, one of which, 1,5 cm long and 0,6 cm broad, is longer than the other three, and corolla, of about 0,6 cm of diameter, with thin cylindrical tube, about 1,5 cm long, externally red, and 4 ovate lobes of white colour. The flowers are bisexual, but present the phenomenon of the heterostyly, with individuals bearing only flowers with short style and long stamina (brevistylous) and other only flowers with style longer than the stamina (longistylous), this favours the crossed fecundation. Obconical indehiscent fruits, with persistent enlarged calyx, usually containing one seed only.
It propagates, though with some difficulty, by seed, previously kept in water for one day, in organic draining loam maintained humid at the temperature of 24-26 °C, with germination times of 2-4 weeks, and by cutting and air layering.
Species of very important ornamental and landscape value, but quite rare in cultivation, that would deserve a better diffusion in the parks and gardens of the tropical and subtropical regions due to its spectacular blooming that lasts for most of the year, with the single flowers keeping intact for various months, to be utilized as isolated specimen, for hedges or at the margins of the alleys.
It requires full sun, or at the most, a slight shade, and soils rich of organic substance, draining, maintained almost constantly humid, but without stagnations, even if it can stand when adult short dry periods. The prunings after the blooming contribute in maintaining a compact posture and in stimulating the blooming. It well adapts to the cultivation in pot, with draining loam rich of humus, for the decoration of open spaces or for being sheltered in protected ambient, where the climate does not allow the continuous permanence in open air, in a most possibly luminous position, with lowest values not under the 16 °C. The waterings must be regular in summer, more spaced in winter, allowing the substratum to slightly dry up before watering again, and the monthly fertilizations, from spring to autumn, utilizing preferably a balanced product with microelements at half the dosage shown on the package.
Synonyms: Alberta isosepala Baker (1882); Dirichletia insignis Vatke (1885); Dirichletia ternifolia Baker (1887); Carphalea ternifolia (Baker) Homolle (1937).